Saturday, 22 June 2013

Cholesterol

One of the main concerns in the health industry and causing strain on the NHS in the UK is due to obesity. The graph below shows an increase in the amount of people who are overweight, obese and extremely obese since the 1960s.

(Reference:
http://www.brainfacts.org/across-the-lifespan/diet-and-exercise/articles/2010/obesity-and-the-brain/)







With a rapidly increasing rate of overweight people in the population, there are increasing levels of Diabetes, High blood pressure, stroke, Cancer, heart disease and many other chronic illnesses. There have been more law enforcements on different types of food particularly fast food to display the levels of salt, saturated fat and sugars. However the major contributer to heart disease and atherosclerosis which is cholesterol. Cholesterol blocks artery walls, and reduce the amount of blood supplying the heart with oxygen. Oxygen is essential so aerobic respiration can occur, so the heart can contract, so a lack can also lead to a myocardial infarction (heart attack.) Due to this high risk, i believe strongly on food packaging there should be information regarding cholesterol, and the ingredients which lead to increased levels. The salt concentration allows people to become aware of how they're contributing to their high blood pressure, and there should be the same for cholesterol.

There is confusion about whether cholesterol is beneficial for the body or harmful, and the answer is that is is both. It goes without saying, that cholesterol is essential for the body just like salt or sugar is, it is used in the production of Vitamin D, membranes, bile salts and steroid hormones. Cholesterol is an insoluble lipid and its therefore carried in the blood attached apoproteins and when they bind to cholesterol they become lipoproteins. The are two types:  LDLs (low density lipoproteins) which take cholesterol from the liver and towards body tissues. Or HDLs (high density lipoproteins) which return cholesterol from tissues back to the liver. Another argument against having cholesterol levels on food, is because scientific evidence shows that the diet has little effect on the cholesterol levels and it is down to familial hypercholesterolaemia. This is a genetic condition where the sufferer is deficient in the receptor which allows LDL cholesterol to be reabsorbed by the liver. This leads to a build up of cholesterol in the blood, because more is leaving the liver then being returned, this theory indicates its due to genetic inheritance. Nevertheless, even though research supports this idea, I would personally argue how does this support the relationship between obesity and heart disease, or bad diets and heart disease?

The 'wonder drug' which prevents coronary heart disease is know as Statins, which was approved for sale in 1987. They prevent heart disease by lowering cholesterol levels, and they work by inhibiting the the enzyme HMG-CoA reductase which plays a major part of synthesis in the liver. Statistics:

  • The risk of fatal coronary heart disease decreased by 29% when taking statins. 
  • One in three people over the age of 45 currently takes a statin.  


To the left Lovastatin a compound isolated from Asperguillus terruis, which was the first marketed statin. Reference: http://en.wikipedia.org/wiki/Statin
Source:
Biological Science Review, Volume 22, Number 3, February 2010

Sunday, 16 June 2013

Ketones

I'm going to apologize for no recent posts on my blog, I have only just finished my AS levels and although reading around medicine I have had limited time to write a post on something that interests me.

As I've mentioned on previous posts, I have quite a large interest in Diabetes (Type 1 in Particular) since my sister was diagnosed. Yesterday morning I was urged to research about high blood sugars and ketones after my sister was taken to hospital due to her line from her pump becoming blocked.

Although, the body is in continual production of ketones, formed in the liver, the concentration is always very low and are usually undetected by urine tests. However in someone with Diabetes,  an insufficient supply of insulin leads to hyperglycemia which in turn leads to a ketones build up. They build up because the glucose causing the high blood sugar level cannot enter cells and remains in the blood, so the bodies fat and protein is alternatively burnt, to provide energy.


Structure of a Ketone: As shown below, is a oxygen double bond attached to a carbon chain.
(The only previous time I have come across a ketone is in the oxidation of secondary alcohols in the presence of acidified potassium dichromate, however in the body the formation is very different. )


In the picture the first ketone structure is known as acetone, which can be smelt in the breath of someone with ketosis. Ketosis is when a high concentration of ketones build up and they can be detected in the blood stream, because synthesis is higher the utilization. 

Sources: